It is the fact that groceries are only one part of the shopping relationship it has built with millions of American households. It offered consumers a combination of low prices, enormous stores and a huge range of products, using its scale to put pressure on traditional supermarkets. Today, however, describing Walmart simply as America’s biggest supermarket would miss the bigger story. Walmart is increasingly becoming an entire retail ecosystem, combining physical stores, online shopping, grocery delivery, advertising, membership services, financial products, technology and an enormous supply chain. Its grocery operation remains at the centre of that ecosystem, but the company can use the strength of its other businesses to reinforce its position in food.